Taking IRTC images

General info.

On the Linux computer of choice, open a terminal window and type "rdesktop -u testcamera -g 700x840 irtc -z". (This is aliased as "startirtc" for user LBTO, lbcobs, telescope.) That action should bring up a pop-up login. (The -z sets compression, but we haven't measured whether it helps or not.)

Screenshot of the IRTC GUI

• Plot of Strehl Ratio versus guide star magnitude:
  

Turning On the Camera

Turn switch in the lower right treehouse (left door as you face the treehouse) labelled "IRTC2 power supply".

Taking Images during the night

The toolbars are relatively self-explanatory for direct operation of the camera. Set the exposure time in microseconds, the frame rate for multiple exposures, and the number of exposures if desired. The exposure time is the controlling variable if the two are in conflict. For actual rapid framing (not immediately relevant to active optics commissioning), the frame rate for very short exposures is limited to the range of 15 to 60 frames per second. The system is such that the frames will be taken with the exposure time and speed requested, but then are transfered to the local (PC) disk individually, which takes some time. There is a check box to enable the Peltier cooler, which should be on for lower dark-current operation. Typical maximum exposure times at H are 3-5 seconds before saturation.

The optics configuration toolbar shows a status indicator box - green, yellow, or red; a choice of one of three check boxes sized indicatively for the three different fields of view, a choice of filter position, and a lens configuration file. In order to get a valid configuration, the filter must be selected first then the field of view. If the configuration is undefined (e.g., by changing the filter and not re-checking the field of view box), the status box may still be green, but an error message will appear under the image display window. Alternate lens configuration files are given, in case future use patterns calls for that, but it is recommended for now to use the default configurations.

There are several modes for taking data. Movie mode (by clicking on the movie camera icon) frames continuously using the given exposure time. The pull-down menu from the down arrow button allows for saving (on the camera's local disk) single exposures, a sequence of multiple exposures, or looping repeatedly through the set exposure sequence, saving everything until the process is stopped by clicking on another mode. To take a sequence, set the exposure time in the first box in the toolbar and the number of exposures in the third box. (Turn off movie mode, if not done already.) If desired, type a prefix in the right-hand box on the lower toolbar. Press the button to the right of the box with the number of exposures to record a sequence. Multiple exposures are saved as FITS datacube files.

When the IIF-based higher level control is used, a single exposure is saved to the /Repository/ directory accessible to the mountain network. Such an exposure has a full FITS header with all the desired telescope information. Multiple exposure datacubess are saved usually on the local disk, and can be saved to the Repository (or another directory of choice) after initially creating a link to that directory on the control PC.

Mounted Network Disk

On 20080415, Jim Davis has added a network drive (R:) on the IR test camera PC that maps directly to the repository directory on the NFS server, via Samba. This should connect whenever you login to irtc. To send irs-generated sequences directly to the Repository, set the FITS path in the camera control text box to 'R:'.

Obviously, images stored on the local disk can be transfered to the Repository as well by dragging and dropping from C:\SNAPS\FITS\relevant data directory. For good housekeeping, it then might be worthwhile to create a subdirectory in the Repository: there is one called EF being used for early experiments. The locally stored images (not retrieved through irs) do not have full telescope information in their FITS headers.

One toolbar allows the creation of up to three user-defined regions of interest in the detector format. When activated, the detector readout is limited to those subregions, allowing yet faster frame rates. There is also a zoom-unzoom button that affects the magnification shown in the display window. Both of those toolbars are typically hidden, to allow more of the image format to be visible.

TROUBLE SHOOTING Mapped Network Drive

If the R: drive mapping is broken do this to reestablish it...

Bring up a "Windows Explorer" window.
Select the "Tools" menu.
Select "Map Network Drive" option.

In the "Map Network Drive" window...
Select "R:" from the "Drive" drop down selection list.
Enter "\\archive\newdata" in the "Folder" field.
Select the checkbox to reconnect at restart

Set the user id to be used for the connection.
Select "Connect using a different user name".

In the "Connect As..." window...
Once this is done the drive will be mapped.
Enter "LBTO" user id in the "User name" field.
Enter the password for the "LBTO" user in the "Password" field.
Select OK

At the "Map Network Drive" window...
Select "Finish"

Turning Off the Camera

When the control window is shut down. it leaves the Peltier cooler in whatever state its check box indicates. To preserve the lifetime of that cooler, it should be turned off when the camera is not in use, by unchecking the enable box before closing down the control window.

Normally the power switch in the treehouse is left on all the time during normal observing operations.

Commands.

Using IDL;

Set the focal station where the IRTC is mounted. Authorize the irc Authorize the IRTC from the TCS.

The takepic task queries and prints out the camera parameters as they are currently set, then sets the exposure time and frame rate before taking a single exposure. The other camera parameters (subarrays, filter, FOV, etc., are all set on the camera GUI running on the windows control computer and are not set through the IRTC interface. The takepic command executes the following series of IRTC calls (the 2300000 is the exposure time in microseconds):

• GetIRParam
• GetFilter
• GetFOV
• SetIRParam 2300000. 1.
• GetImage

Simply way to take an exposure.

NOTE Any changeS in the camera setup has to be done using the IRTC GUI.

• Disable snapshoot or live view from the IRTC GUI.
• Use idl commands to get parameters or to get images

>  irc_getirparam
>  irc_getimage

Store data.

The data are stored in /newdata. example:

irtc.20120331.001447.fits 

-- JuanGuerra - 31 Mar 2012

• IRTC_screen: